Car wash conveyor

ABSTRACT

A conveyor for an automobile or car washing system includes endless drive chains having a plurality of dollies removably engaged therewith. The drive chains are continuously driven about spaced sprockets and the dollies are selectively interconnected with the drive chains. The dollies include pushers which travel along a wheel-engaging path to move the wheels of the car along a predetermined path through the car washing system. Dollies are connected to the drive chains upon actuation of a switch sensing the presence of the car or by other electrical or mechanical means.

United States Piltfilit Beer et al.

[ 51 Apr. 3, 1973 CAR WASH CONVEYOR o v A98 0 32 w /40 Q .2

l0/l968 Smith ......l04/l72 B 10/1969 Van Brakel ..104/172 B Primary Examiner-- Gerald M. Forlenza Assistant Examiner-R0bert Saifer Attorney-Seidel, Gonda & Goldhammer s7 ABSTRACT A conveyor for an automobile or car washing system includes endless drive chains having a plurality of dollies removably engaged therewith. The drive chains 'are continuously driven about spaced sprockets and the dollies are selectively interconnected with the drive chains. The dollies include pushers which travel along a wheel-engaging path to move the wheels of the car along a predetermined path through the car washing system. Dollies are connected to the drive chains upon actuation of a switch sensing the presence of the car or by other electrical or mechanical means.

8 Claims, 9 Drawing Figures PATENTEDAPN I975 3,724,390

SHEET 1 BF 7 F/GJ.

INVENTORS CARL C. BEER SHERMAN L. LARSON A TTORNEYS PATENTEDAFR 3 ma SHEET 2 BF 7 //VVNTO/?$ CARL C. BEER SHERMAN L. LARSON BY MM W mum ATTORNEYS PATENIEMPRB ms 3, 724; 390

sum 3 BF 7 INVENTORS CARL C. BEER SHERMAN L. LARSON ATTORNEYS PAIENTEDAPR3 I975 3,724,390

o-"--FU' I JLJ I i [LIL v fNVENTORS CARL C. BEER SHERMAN L. LARSON Q BY ATTORNEYS PATENTEDAPR 3 I975 SHEET S U? 7 ATTORNEYS PATENTEDAPR 3 I975 SHEET 8 BF 7 N 0 M 5 A Mi TE N N fim WM M 5 BY WM MWM ATTORNEYS PATHH'EDAFREK IBIS 3,724,390

SHEET 7 BF 7 INVENTORS CARL C. BEER SHERMAN L. LARSON MM KM? ATTORNEYS CAR WASI-I CONVEYOR The present invention relates to a conveyor, and more particularly, to an automobile conveyor haying safety features incorporated therein.

Automobile conveyors wherein endless chains are supported by spaced sprockets, one or more of which is driven, have heretofore been proposed. Conventionally, dollies having pusher members have been coupled to the chains at spaced intervals.

Although quite satisfactory in terms of pushing performance, structures of the conventional type are known to present safety hazards in use. For example, in utilizing conventional mechanisms, if a person were to accidentally step into the path of a dolly, his foot could be caught and wedged between the dolly and the floor. Because of the conventional securement of the dolly and drive chains, there would be little opportunity for the individual to extricate himself without incurring serious injury. Furthermore, prior art conveyors of this sort may also encounter various types of mechanical difficulties. For example, debris, tools or the like, if left adjacent the conveyor, are likely to be wedged between the dollies and the floor, thus causing jamming or breaking of the conveyor.

Furthermore, most prior art conveyors are provided with dollies fixedly located at spaced points therealong. The removal of a damaged dolly and connection of a new dolly to the conveyor has been found to be time consuming and to cause considerable downtime of the entire car washing system.

It is an object of the present invention to provide an automobile conveyor which overcomes the deficiencies of prior art automobile conveyors discussed above.

It is another object of the present invention to provide a novel automobile conveyor.

It is a further object ,of the present invention to provide an automobile conveyor of the type comprising endless chains and dollies, wherein safety features are provided to minimize the possibility of accidents or injuries due to operation of the conveyor.

It is yet a further object of the present invention to provide a dolly which is symmetrical and which can be selectively engaged and disengaged from the conveyor at any location along the upper or lower track of the conveyonl It is a further object of the present invention to provide a constant conveyor chain take-up to eliminate the necessity of periodically adjusting the conveyor chains.

Other objects will appear hereinafter.

In a presently preferred form of the invention, the foregoing and other objects are realized by an automobile conveyor comprising endless chains supported by spaced sprockets. The chains have a drive flight and a return flight. Drive tracks are disposed adjacent the drive flight and the return flight. A magazine is pro vided for the storage of dollies and is located beneath the return flight of the endless chains. Dollies are adapted to be removably connected to the drive chains at spaced points therealong. The dollies have wheels for rollingly engaging the guide tracks. The dollies are provided with pusher means for driving contact with the wheels of a car. Plural pusher means are coupled to dollies and are adapted to rotate about a horizontal axis. The dollies may be easily disconnected from the drive chains upon contact with an obstruction.

The dollies may be selectively interconnected with the drive chains. A-piston cylinder arrangement is provided for interconnecting the dollies with the drive chains. A gripping means is provided and is connected to a piston rod for engaging a dolly in the magazine section and moving the dolly into a position where it will be engaged by the conveyor chains. A plurality of dollies are stacked to the magazine track section. The dollies contact and open a hinge plate which is moved to allow the dolly to enter the upper portion of the track. The hinge plate normally covers the opening through which the dollies move.

The use of selectively engageable dollies permits more cars per hour to be processed at slower conveyor speeds. The dollies are symmetrical and thus the possibility of improper installation is eliminated. The dollies can be placed on or removed from the conveyor at any location along the upper or lower track. While it has been already stated that the dollies may be disengaged from the chains if any obstacle is encountered between the dolly and the tire track, another safety feature is that when there are no cars being conveyed, there will normally be no dollies in the upper track to cause mishaps.

The dollies utilized are designed to engage on standard chain links. The conveyor track is sufficiently wide to accept the new wire tread tires. The hinge plates provide a smooth track for tires to roll upon and there are no exposed track openings for the tires to roll over.

There is provided a constant conveyor chain take-up which eliminates the problem of periodic adjustments of the conveyor chains. The constant take-up also eliminates the oft-encountered problems of overtightening or insufficient tightening of the conveyor chains. 7

The invention is deceptive in its simplicity and substantially reduces the chances of costly field service problems. The conveyor may be operated completely automatically by connecting'a dolly thereto after a car has tripped a switch. There may also be a remote control switch to override the automatic control switch.

For the purpose of illustrating the invention there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIG. 1 is a diagrammatic top plan view of the automobile conveyor of the present invention;

FIG. 2 is a top plan view, partially broken away, of one end of the conveyor of FIG. 1;

FIG. 3 is a section view taken along the line 3-3 of FIG. 2;

FIG. 4 is a-top plan view, partially broken away, of the other end of the conveyor shown in FIG. 1;

FIG. 5 is a section view taken along the line 5-5 of FIG. 4;

FIG. 6 is a section view taken along the line 6-6 of FIG. 5;

FIG. 7 is a side elevation view of the magazine section of the conveyor;

FIG. 8 is a section view taken along line 8-8 of FIG. 1; and

FIG. 9 is a perspective view of the dolly utilized in the present invention.

Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, there is shown in FIGS. 1-9 a conveyor generally indicated by the reference numeral for use in a car washing system, automatic or otherwise. The conveyor 10 includes a drive end 11 having a drive box 12 and an idler end 14.

The conveyor includes an upper track 16. Endless drive chains 18 and 20 are wound about drive sprockets 22 and 24 and idler sprockets 26 and 28, respectively. The drive sprockets 22 and 24 are fixedly mounted on a shaft 30. The idler sprockets 26 and 28 are fixedly secured to the shaft 32. The shaft 32 has its end suitably journaled for rotation and is adapted to freely rotate with the sprockets 26 and 28.

A pair of sprocketed wheels 34 are secured at one end of shaft 30. The wheels 34 are connected by chains 38 to sprocketed wheels 36 mounted on the driven shaft 42 of gear reduction unit 44. The gear reduction unit 44 is, in turn, connected with a motor 40 through a variable speed drive generally designated as 46. The ends of shaft 30 are suitably journaled for rotation.

All of the drive components are mounted on a structural steel frame generally indicated by the reference numeral 48. The steel frame with the drive components secured thereto is mounted on four V-grooved wheels which ride on tracks. Only the front two V-grooved wheels 50 and 52 are shown. The wheel 50 rides on V- track 54 and the wheel 52 rides on V-track 56. A constant conveyor chain take-up is provided to prevent slack in the conveyor chain. i

The take-up components include a pair of cylinders 58 and 60, each of which has one end fixedly secured to a permanent wall. As shown, cylinder 58 is connected through a clevis 62 to a wall 64. Cylinder 60 is connected through a clevis 66 to wall 64. Constant pressure is applied behind the piston (not shown) within the cylinder 58 in order to provide a constant force tending to extend'the piston rod 70 of the cylinder 58. Constant pressure is also applied behind the piston (not shown) of the cylinder 60. Both the cylinder 58 and the cylinder 60 apply a constant force in a direction such that all slack within the conveyor chains 22 and 24 is eliminated. By application of a constant predetermined force to the cylinders 58 and 60 excessive tension on the drive chains may be avoided.

Constant pressure on the conveyor chains 22 and 24 effects a constant chain slack take-up. In addition to the cylinders 58 and 60, there isa mechanical safety which includes a pawl cooperating with a toothed rack. The pawl will override the rack in one direction, but will provide a lock should the cylinders fail and the drive components begin to move in a direction permitting slack in the conveyor chains.

A wheel of a vehicle generally indicated as 74 is shown at the entrance end of the conveyor in FIG. 3. Suitable guide rails 76 and 78 are provided to maintain the wheel 74 on the conveyor 10. The wheel 74 is adapted to ride upon a flat plate or platform 80. The platform 80 is a generally C-shaped channel member having downwardly depending legs 82 and 84. Suitable supporting structure from the conveyor frame generally indicated by the reference numeral 85 may be utilized to support the platform 80.

Chain support members 86 and 88 (FIG. 8) are provided and are also supported by support structure connected to the frameof the conveyor 10. C-shaped channel members 90 and 92 are also supportedby the frame of the conveyor. The C-shaped members 90 and 92 may be welded or otherwise secured to the members 86 and 88. v

Dollies 94 (FIG. 9) are adapted to be conveyed by the endless drive chains 18 and 20. The dollies 94 are symmetrical. Each dolly includes a pair of pusher members 96 and 98. The pusher members are adapted to freely rotate on shafts 100. The shafts 100 have their ends engaged in upstanding flanges 102. The pusher.

members 96 and 98 may rotate with or be freely rotatable about the shafts 100.

The dollies may be made of ductile iron castings. Each casting is provided with pairs of symmetrically downwardly depending teeth 104 and 106. The teeth are adapted to be engaged by center links of the endless drive chains 18 and 20. The downwardly depending teeth 104 have freely rotatable hardened steel wheels 108 associated therewith. The downwardly depending teeth 106 have freely rotatable hardened steel wheels 110 associated therewith. The forward pusher or roller 96 or 98 is adapted to engage car tire 74 and push the same along the conveyor track. The roller not used for pushing the car permits smoother transfers around sprockets and adjoining track sections. The inactive pusher has a dual function inasmuch as each dolly is completely symmetrical and, should excess wear occur to either downwardly depending teeth 106 or pusher 98, the dolly 94 may be rotated 180 and teeth 104 and pusher 96 utilized. Hence, upon rotation of dolly 94, the center links of the drive chains 18 and 20 will engage the teeth 104 and the pusher 96 will engage the car tire. Since there is no mechanical interconnection between the dollies and the drive chains, the dollies can be operably associated with or removed fromthe drive chains at substantially every location above and below the floor of the conveyor. The use of symmetrical dollies prevents the dollies from being improperly connected to the drive chains.

A safety feature provided is that should a persons foot be caught between the platform 80 and the dolly 94, the dolly would not cause serious damage to the person's foot. Hence, the dolly would either rise high enough to disengage the dolly from the drive chains or there would be sufficient freedom for one to withdraw ones foot without causing serious injury.

The wheels 108 and l 10 of the dollies are adapted to ride upon the C-shaped supports or channels 90 and 92. As can be readily seen in FIG. 8, the pusher members will not ride upon the plate 80 thus preventing excess wear to the pusher members.

The conveyor 10 includes a return track 112 and a magazine section 114. A plurality of dollies 94 are stacked in the magazine section (see FIG. 3). After an automobile has been driven onto the conveyor,'a dolly is brought up into engagement with the tire of the automobile. To this end, a cylinder 116 is provided at the entrance end of the conveyor 10. A piston rod 118 extends from cylinder 116 and has a dolly engaging mechanism 120 secured thereto.

The dolly engaging mechanism 120 is adapted to engage a dolly 94 and move the same until the dolly is engaged by the conveyor chains 18 and 20. A guide plate 122 is provided to guide the dolly engaging mechanism during movement of the piston rod 118 upwardly as shown in FIG. 3. The dolly engaging mechanism is provided with rollers 124 and 126, which engage the guide plate 122. The dolly engaging mechanism 120 includes a bar 128 which is adapted to engage a dolly 94 and move the same upwardly as the piston rod 118 is withdrawn. Fluid is fed through conduits 130 and 132 to effect desired movement of the piston rod 1 18.

A blocking member 134 is secured to the bar 118. The blocking member134 is provided so that as the dolly is moved upwardly by the dolly engaging member 120, a second dolly will be blocked from moving into the position of the first dolly. Hence, the next dolly will only be permitted to move after the dolly engaging member 120 has been returned to its lowermost position as shown in FIG. 3.

An arcuate guide plate 136 is spring-urged toward the idler ratchets 26 and 28. The arcuate guide plate 136 will be cammed away from the idlers 26 and 28 by a dolly 94. The spring urged arcuate guide plate 136 insures a constant engagement between the dolly 94 and the drive chains 18 and 20. Suitable tension springs 138 may be connected to a V-shaped bracket 140 secured to the arcuate guide plate 136 to insure constant bias of the guide plate 136 toward the idler ratchets 26 and 28.

As the piston rod 118 is moved upwardly, the dolly engaging mechanism 120 will lift a dolly from the magazine section 114 and move the dolly upwardly. The forwardmost teeth of the dolly will be engaged by the center links of the drive chains 18 and and the dolly will be conveyed onto the upper track 16. A suitable hinge plate 142 is adapted to overlie the opening through which the dolly will emerge. The dolly will cam the hinge plate 142 about its pivot shaft 141 to permit the dolly to exit onto the upper track 16. The dolly will then be in a position to engage the tire of the automobile. The hinge plate may be spring-biased to return to its original position, or may be permitted to return to its original position by gravity. The hinge plate 142 is provided so that the tires of the automobile will not have to receive jolts due to gaps in the conveyor track. The dolly will convey the automobile through the various car wash stations.

A cover plate 144 is provided at the exit end of the conveyor. The cover plate 144 allows the car to continue moving without having the tires thereof roll over any track opening. The cover plate has upstanding lugs 146 and 148 secured thereto. The forward end of the dolly will contact the lugs 146 and 148 and cam the cover plate 144 in the direction of movement of the dolly as shown in FIG. 5.

The cover plate 144 has an arcuate guide plate 150 integral therewith. SUitable springs 152 urge the cover plate 144 and guide plate 150 into the position shown in FIG. 5. The arcuate guide plate 150 will maintain the dolly in close contact with the drive chains 18 and 20 as the dolly is conveyed to the return track 112. The cover plate 144 and the arcuate guide plate 150 are mounted on a shaft 154 and pivot thereabout. As the dollies contact the lugs 146 and 148 and move the cover plate 114 in the direction of the movement of the dollies, the tire of the car will also be moved off the conveyor 10.

The dollies 94 will be conveyed in an inverted condition along the return track 112. The return track 112 communicates with and merges into the magazine section 114.

The return track 112 includes a pair of guide plates 152. The rollers of the dollies are adapted to ride upon' the guide plates 152. A center plate 154 is provided immediately before the magazine section and return track merge. The center plate 154 will prevent the forwardmost rollers of the dolly 94 from entering into the magazine section due to contact between the center plate 154 and the pusher members 96 and 98. However, the rearwardmost roller on the dolly 94 will enter the magazine section as shown in FIG. 7. The magazine section 114 includes rearward roller supports 156 and forward roller supports 158.

The sloping portion of center plate 154 will provide a smooth transition for the rearward rollers 108 of the dollies from the return track to the rearward roller supports 156. The same sloping center plate 154 provides for a similar transition of the forward rollers 110 from the return track to the forward roller supports 158. The magazine track will be sloped toward the idler end of the conveyor as shown in FIG. 3, so that the dollies 94 will tend to move by gravity into a stacked position as shown in FIG. 3. Furthermore, slight slack in the chains will permit the chains to engage the upstanding teeth on the dollies to engage by friction and convey the dollies for a substantial distance so that an initial movement is imparted to the dollies.

Upper track section 164 at the exit end of the conveyor is telescopically received within the main plate or platform 80. The track section 164 moves with the drive components so that as the cylinders 58 and 60 move the drive components, a constant track surface is presented. A lower track section 165 is telescopically received within a lower track plate 167. Plate 167 provides support for the pushers on the dollies as the do]- lies are conveyed to the return track. Track section 165 moves with the drive components so that a constant support for the dollies is provided.

In operation of the conveyor, a single dolly may be utilized to push the front tire and a safety dolly could be brought up approximately 3 feet behind the rear tire as a precaution in the event the car jumps the first dolly. This is usually not necessary and is not preferred since twice the number of dollies will be needed. Accordingly, it is preferred to push the cars by the rear tires with a single dolly.

As the front tire of a car enters the conveyor, it may pass over the entrance hinge plate 142 and may trip a switch which may actuate a stepping relay to set up the circuit for picking up a dolly. As the rear tire enters over the entrance hinge plate it may trip the same switch. The later signal will immediately call for a dolly to be picked up by the dolly carriage and placed into position to be engaged by the moving conveyor chains. The tire trip switch will be located at the proper location so that cars can be driven onto the conveyor in close proximity and the dolly will engage the tire when 3 to 4 feet of clearance is obtained between cars to insure proper performance by the various parts in the car wash apparatus. Alternatively, dollies can be called for in any other desired manner including a manually operated switch for controlling operation of cylinder 1 16.

As the dolly 94 engages the conveyor chains, it also engages the guide plate 136, which will hold the dolly in contact with the drive chains until the dolly reaches the entrance hinge plate. The dolly will lift the hinge plate to permit the dolly to come into position on the upper track behind the tire. The dolly will contact the tire andpush the car along the conveyor until the car reaches the exit end.

As the dolly pushes the tire onto the cover plate 144,

it proceeds to contact the lugs on the cover plate caus-' ing the cover plate to move in the same direction as the car is traveling. This motion causes the tire to roll off the cover plate and allows the dolly to enter the opening in the track and proceed around the drive sprockets.

As the dolly proceeds around the drive sprockets it is held onto the chain by the arcuate guide plate 150. The pushers 96 and 98 contact the arcuate guide plate 150 and the lower track section 165 and lower track plate 167. After the dolly enters the return track the rollers or wheels 108 and 110 ride upon the guide plates 152. The dollies will remain engaged with the drive chains until they reach the magazine track section.

As each dolly approaches the magazine track it is positioned by contact between the pushers 96 and 98 and center plate 154 so that the leading side wheels transfer to an upper track and the trailing side wheels transfer to a lower track. This causes the dolly to unhook from the conveyor chains but the dollies keep friction contact with the chains which carry them with the aid of gravity, to their stacked position in the magazine section. The dollies will be stacked until picked up for another cycle.

A further feature of the invention is the provision of an automatic mechanism to provide a car pushing member upon demand. Hence, no dollies need be on the track when cars are not in position to be conveyed through the car washing system.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

We claim:

1. A dolly for use with a conveyor in a car washing system, said dolly being symmetrical and comprising a main body portion, said main body portion having upstanding flanges, a pair of pusher rollers rotatably supported by said flanges, said body having front and rear wheels rotatably secured thereto and said body having downwardly depending teeth adapted to be engaged by the center links of a conveyor chain.

2. A conveyor for a car washing system comprising a pair of endless drive chains supported by pairs of spaced sprockets to provide a drive flight and a return flight, a plurality of vehicle wheel pushers being adapted to be removably connected to the drive chains, drive means for driving one pair of spaced sprockets, a guide track disposed adjacent said drive flight, a return track disposed adjacent said returnflight, said pushers being operatively associated with said drive chains for movement on said guide track and said return track, said return track merging into an inclined magazine track, wherein said pushers are permitted to move by gravity down said magazine track, said magazine track being adapted to store said wheel pushers until a demand is made for said wheel pushers, means operatively associated with said conveyor for removably coupling said pushers to said drive chains, each said pusher comprising a dolly having downwardly depending teeth, said teeth being on both sides of said dolly adjacent the end facesthereof, center links on said drive chains cooperating with said downwardly depending teeth to drive said pushers, said pushers being otherwise unconnected to said endless chains.

3. A conveyor for a car washing system comprising a pair of endless drive chains supported by pairs of spaced sprockets to provide a drive flight and a return flight, a plurality of vehicle wheel pushers being adapted to be removably connected to the drive chains, drive means for driving one pair of spaced sprockets, a guide track disposed adjacent said drive flight, a return track disposed adjacent said return flight, said pushers being operatively associated with said drive chains for movement on said guide track and said return track, said return track merging into a magazine track, said magazine track being adapted to store said wheel pushers until a demand is made for said wheel pushers, means operatively associated with said conveyor for removably coupling said pushers to said drive chains, gripping means at the entrance end of said conveyor, said gripping means being adapted to move a pusher upwardly into engagement with said drive chains, said gripper means having a blocking means associated therewith to prevent further pushers from jamming the gripping means.

4. A conveyor as set forth in claim 3 wherein said I gripping means moves said pusher upwardly against an arcuate camming plate, said plate being spring urged to force said pusher into communication with said drive chains, an arcuate plate at the exit end of said conveyor for insuring communication between said pusher and said drive chains as said pusher is conveyed from said guide track to said return track.

5. A conveyor for a car washing system comprising drive means to provide a drive flight and a return flight, a plurality of vehicle wheel pushersbeing adapted to be removably connected to the drive means, a first track disposed adjacent said drive flight, a return track disposed adjacent said return flight, said pushers being operatively associated with said drive means for movement on said first track and said return track, said return track merging into a magazine track, said magazine track being adapted to store said wheel pushers, means operatively associated with said conveyor for moving a pusher from said magazine track and removably coupling said pusher to said drive means, gripping means at the entrance end of said conveyor, said gripping means being adapted to move a pusher upwardly into engagement with said drive means, said gripper means having a blocking means associated therewith to prevent further pushers from jamming the gripping means.

6. A conveyor as set forth in claim 5 wherein said gripping means moves said pusher upwardly against an arcuate camming plate, said plate being spring urged to force said pusher into communication with said drive means, an arcuate plate at the exit end of said conveyor for insuring communication between said pusher and said drive means as said pusher is conveyed from said first trackto said return track.

7. A conveyor for a car washing system comprising drive means to provide a drive flight and a return flight, a plurality of vehicle wheel pushers being adapted to be removably connected to the drive means, a first track disposed adjacent said drive flight, a return track disposedadjacent said return flight, said pushers being operatively associated with said drive means for movement on said first track and said return track, said return track merging into a magazine track, said magazine track being adapted to store said wheel pushers, means operatively associated with said conveyor for moving a pusher from said magazine track and removably coupling said pusher to said drive means, said pusher comprising a dolly having pusher rollers and front and rear guide rollers, said dolly being adapted to roll on said front and rear guide rollers for a substantial portion of movement of the dolly along the drive and return flight of the conveyor, a base plate on said dolly supporting said pusher rollers, said base plate being adapted to provide support for movement of the dolly for a slight portion of the movement of the dolly along the drive and return flight of the conveyor, transfer means for transferring said dolly from said return track into said magazine track, said transfer means including a plate preventing the front guide rollers on said dolly from falling into said magazine track, guide rails for said front guide rollers, said rear guide rollers of said dolly being permitted to drop into said magazine track, said guide rails merging into an upper track support for said front guide rollers for said magazine track.

8. A conveyor as set forth in claim 7 wherein said dollies are stored in said magazine track in a substantially vertical disposition, said magazine track being inclined toward said coupling means, said dollies being conveyed to a stacked position by frictional engagement of said dollies and said drive means combining with the gravitational movement of said dollies down the inclined magazine track. 

1. A dolly for use with a conveyor in a car washing system, said dolly being symmetrical and comprising a main body portion, said main body portion having upstanding flanges, a pair of pusher rollers rotatably supported by said flanges, said body having front and rear wheels rotatably secured thereto and said body having downwardly depending teeth adapted to be engaged by the center links of a conveyor chain.
 2. A conveyor for a car washing system comprising a pair of endless drive chains supported by pairs of spaced sprockets to provide a drive flight and a return flight, a plurality of vehicle wheel pushers being adapted to bE removably connected to the drive chains, drive means for driving one pair of spaced sprockets, a guide track disposed adjacent said drive flight, a return track disposed adjacent said return flight, said pushers being operatively associated with said drive chains for movement on said guide track and said return track, said return track merging into an inclined magazine track, wherein said pushers are permitted to move by gravity down said magazine track, said magazine track being adapted to store said wheel pushers until a demand is made for said wheel pushers, means operatively associated with said conveyor for removably coupling said pushers to said drive chains, each said pusher comprising a dolly having downwardly depending teeth, said teeth being on both sides of said dolly adjacent the end faces thereof, center links on said drive chains cooperating with said downwardly depending teeth to drive said pushers, said pushers being otherwise unconnected to said endless chains.
 3. A conveyor for a car washing system comprising a pair of endless drive chains supported by pairs of spaced sprockets to provide a drive flight and a return flight, a plurality of vehicle wheel pushers being adapted to be removably connected to the drive chains, drive means for driving one pair of spaced sprockets, a guide track disposed adjacent said drive flight, a return track disposed adjacent said return flight, said pushers being operatively associated with said drive chains for movement on said guide track and said return track, said return track merging into a magazine track, said magazine track being adapted to store said wheel pushers until a demand is made for said wheel pushers, means operatively associated with said conveyor for removably coupling said pushers to said drive chains, gripping means at the entrance end of said conveyor, said gripping means being adapted to move a pusher upwardly into engagement with said drive chains, said gripper means having a blocking means associated therewith to prevent further pushers from jamming the gripping means.
 4. A conveyor as set forth in claim 3 wherein said gripping means moves said pusher upwardly against an arcuate camming plate, said plate being spring urged to force said pusher into communication with said drive chains, an arcuate plate at the exit end of said conveyor for insuring communication between said pusher and said drive chains as said pusher is conveyed from said guide track to said return track.
 5. A conveyor for a car washing system comprising drive means to provide a drive flight and a return flight, a plurality of vehicle wheel pushers being adapted to be removably connected to the drive means, a first track disposed adjacent said drive flight, a return track disposed adjacent said return flight, said pushers being operatively associated with said drive means for movement on said first track and said return track, said return track merging into a magazine track, said magazine track being adapted to store said wheel pushers, means operatively associated with said conveyor for moving a pusher from said magazine track and removably coupling said pusher to said drive means, gripping means at the entrance end of said conveyor, said gripping means being adapted to move a pusher upwardly into engagement with said drive means, said gripper means having a blocking means associated therewith to prevent further pushers from jamming the gripping means.
 6. A conveyor as set forth in claim 5 wherein said gripping means moves said pusher upwardly against an arcuate camming plate, said plate being spring urged to force said pusher into communication with said drive means, an arcuate plate at the exit end of said conveyor for insuring communication between said pusher and said drive means as said pusher is conveyed from said first track to said return track.
 7. A conveyor for a car washing system comprising drive means to provide a drive flight and a return flight, a plurality of vehicle wheel pushers being adapted to be removablY connected to the drive means, a first track disposed adjacent said drive flight, a return track disposed adjacent said return flight, said pushers being operatively associated with said drive means for movement on said first track and said return track, said return track merging into a magazine track, said magazine track being adapted to store said wheel pushers, means operatively associated with said conveyor for moving a pusher from said magazine track and removably coupling said pusher to said drive means, said pusher comprising a dolly having pusher rollers and front and rear guide rollers, said dolly being adapted to roll on said front and rear guide rollers for a substantial portion of movement of the dolly along the drive and return flight of the conveyor, a base plate on said dolly supporting said pusher rollers, said base plate being adapted to provide support for movement of the dolly for a slight portion of the movement of the dolly along the drive and return flight of the conveyor, transfer means for transferring said dolly from said return track into said magazine track, said transfer means including a plate preventing the front guide rollers on said dolly from falling into said magazine track, guide rails for said front guide rollers, said rear guide rollers of said dolly being permitted to drop into said magazine track, said guide rails merging into an upper track support for said front guide rollers for said magazine track.
 8. A conveyor as set forth in claim 7 wherein said dollies are stored in said magazine track in a substantially vertical disposition, said magazine track being inclined toward said coupling means, said dollies being conveyed to a stacked position by frictional engagement of said dollies and said drive means combining with the gravitational movement of said dollies down the inclined magazine track. 